Still head condenser



Sept 9, 1947 H. G. HCSRNBACHER Er AL. 2,427,142

STILL HEAD CONDENSER Filed ual-cn 2. 1943 Jnhmtnta Mrsenr Q 6mm/musk mvp rows L' Larp Patented Sept. 9, 1947 STILL HEAD coNDENsEn Herbert G. Hornbacher, Essexville, and Lewis E. Lloyd, Midland, Mich.,` assignors tovCorning Glass Works, Corning, N. Y., a corporation of l New York Application March 2, 1943, Serial No. 477,736

The present invention relates todistilling apparatus but more particularly to improved forms of still heads. s s

`In the last two decades, laboratory distillation technique and equipment has been substantially improved. A considerable number of references have appeared in the literature for laboratory still heads alone. Several earlier publications on still heads have suggested various types of dephlegmators. In the past ten years most of the suggested heads have been of the total condenser type. The majority of these heads have the product take-off rate controlled by using a stopcock `as a variable orifice. The reflux ratio in these heads is a function f both the rate of product take-olf and the rate of distillation and is generally determined by counting the drops of reflux and product. SuchV heads show several operating difculties and undesirable characteristics such as uncertainty' and variability of the reflux ratio or` other major operating difculties such as vdroplets of water sealing the capillaries and superycooling of the product?" Some of these heads are lalso so complicated and fragile as to render them y unsuitable for routine distillation work. Furthermcre, the conventional still head is almost uselessf'for steam fractional distillations. One of the organic liquids being distilled is usually lighter than the other and the heavier settles to the bot- `tom of the take-on? duct and comes out through amount of the lighter liquid-which maybe the desired productreturns as reflux.

The primary object of the present invention is an improved form of still head.

Another Objectis a constant reflux ratio still head.

A further object is a constant reflux ratio still head which may be readily adjusted to operate at any of a plurality of selected ratios.

A still further object is an adjustable constant reflux ratio'still head'suitable for use on large capacity chemical apparatus.

lAnother object is a constant redux ratio "still head suitable for steam distillations. y

d Other objects of the invention will become apparent' from a further perusal of the specification taken in connection with 'the accompanying drawings.v w l In the' drawings 3 Claims. (Cl. 257-34) 1lir ' the partly closed stopcock while a disproportionate Fig. 1 ls a plan view offa still head;

Fig. 2 is a sectional view taken along line =22 of F18. 1;

Fig. 3 is a sectional View taken on line 3--3 of Fig. 2;

Fig. 4 is a view similar to that of Fig. 2, but of a modified form of the invention;

Fig. 5 is a View taken on line f5`5 of Fig. 4.

The still heads shown are based on a, principle, so far as applicants are aware, heretofore unknown. The basic principle of these new heads consists in having a pluralityof condensing surfaces in parallel, one or more surfaces giving product while one or more others give reflux.

These types of heads on laboratory stills have made possible much better distillation with considerably less operator attention and many other advantages over previously suggested laboratory still heads. i.

As heretofore stated, the basic principle of our new still head is the use of a plurality of condensing surfaces in parallel; the condensate from y one or more surfaces being taken as product While that from the remaining surface or surfaces returns as reflux. Since the condensing surfaces are in parallel, the ratio of their condensates is a function only of the geometry of the head and is independent of the vertical fraction of` the condenser which is necessary to condense the vapors at any given distillation rate. Of course, the ratio of the amounts condensed on different surfaces is proportional to the areas only if the heat transfer is similar for the two areasand if the vapors have similar paths to the several condensing surfaces.

The multi-ratio glass still head designs illustrated in Figs. 1-5 have been found most suitable for laboratory application.

In the head shown in Figs. 1-3 the inner sur- 40A face of the tubular condensing wall 30 is divided into segregated vertical strips, each of which densate from a surface between any pair of guide lines 3| may be kept from mixing with the reflux, and can be delivered as product as will be more fully brought out later.

The wall is surrounded by a tubular Water jacket 33 tapered and ground at the bottom to fit into `the ground socket of a fitting and has a water intake tube 34 arranged tangent to the condenser wall 30 so that the water Will take a spiral course through the jacket on its way to an outlet tube 35. cooling iiuid. gives uniform heat transfer conditions all around wall 30 which is a prerequisite for the correct operation of the head assembly.

The head supporting fitting 40 may be built for use of either a thermometer or a thermocouple for temperature indication. The well 4| is provided to accommodate a thermometer or thermocouple and is protected from exposure to super-cooled reflux by a device 42 which defiects the super-cooled reflux draining over the well 4| to one side thereof. To gather product the fitting 40 has a product receiving line 43 having an inlet opening 44 so located within the fitting that the drip point between any pair of the converging guide lines 3| can be aligned thereover in accordance with the ratio of product to reflux desired. Liquid seal or trap 45 in the product line 43 is provided to keep condensing conditions constant. A vent tube 46 extends from the delivery end of line 43 through the wall of fitting 40 and thence projects well up into the interior of the tubular wall 30. As soon as the trap 45 becomes sealed with liquid, vent tube 46 furnishes an outlet `whereby uncondensed low boiling vapors may be exhausted from the still without fluctuations in pressure within the still being caused by the bubbling of such vapors through the trap, or without breaking the seal in the trap and so allowing uncondensed vhigher boiling vapors to pass out through the trap into the product line.

steam distillation Steam distillation may be carried out in the same manner as dry distillation, the Water and organic liquid which condenses in a tube or between guide lines over a product receiving fun- Dstz'llatton of low boiling materials The modified form of head illustrated in Figs. 4 and 5 hasbeen designed for use in separating or purifying -by distillation materials which start to decompose below their boiling points. In this structure the guide lines 5| are arranged on the outer surface of the tubular condenser wall 56. Cooling fluid enters the interior of Wall 50 through a tube 52 and leaves through a tube 53 after having thoroughly washed the inner surface of wall 50. A saw-tooth skirt 54 is fused to and forms a continuation of the bottom end of wall 50 and is arranged to function in the same fashion as the corresponding part of Fig. 2

structure. The product line 64, however, differs slightly from product line 43 of Fig. 2 in that the trap or liquid seal 65 is arranged within the fitting. This prevents boiling of liquid in the trap and consequent breaking of the seal.

In addition to skirt 54, a rod 55 extends from the wall 50 with its free end brought into the axial center of the assemblyand over a reboiler 6| arranged integral with a fitting 60, which,

This swirling action of the at its upper end, has a seat into which the upper end of wall 50 fits. The use of reboiler 6| enables one to accurately determine the equilibrium temperature between the boiling condensate and its vapor. The fitting 60 is of double-wall construction with lthe space between its walls evacuated to reduce heat loss therethrough. The vent tube 56 passes through the double wall of fitting 60 and then projects upward outside of tle wall 50 as most clearly brought out in Fig.

The reboiler 6| is supplied with fluid from a section of wall 50 by rod- 55 and reboiling accomplished by introduction of an electric heating element in a tubular cavity 62 extending into the reboiler. A second thin walled tubular entry-way 63 enables introduction of a thermocouple into the reboiler.

Attention, is directed to the fact that in the structures of Figs. 2 and 4 the glass connections between the fitting 40 and wall 33 and between fitting 60 and wall 50 are water cooled, thereby preventing thermal distribution. of lubricants usually employed in such connections.

As will be readily understood, when using the structures of Figs. 2 and 4 the product-redux ratio is determined -by the fraction of the condensing area between the particular guide lines at the time converging over opening 44. For example, the spacing of the relatively closely spaced pairs of guide lines 3| is such that ratios 10:1, 20:1 and 30:1 are available. Obviously, many more guide lines may be provided if a greater number of ratio selections are desired.

Although in the examples of the invention illustrated the variations of ratio are somewhat limlted, it will be readily understood that the invention contemplates division of the condensing surfaces to obtain any desired ratios and that such variation in structure as well as others may be made without departing from the spirit and scope of the invention.

We claim:

1. In a still head assembly, a support, a condenser mounted on said support and axially rotatable with respect thereto and having a condensing surface thereon, vertically extending ridges dividing said condensing, surface into a series of parallel areas of different width, and collecting means mounted on said support in alignment with an area of .said surface depending upon the rotary position of said still head with respect to said support for the receipt of condensate therefrom.

2. In a still head assembly, a condenser unit comprising a double-walled tubular body having inlet and outlet conduits in communication with the space between the inner and outer walls of said unit, guide lines dividing the inner surface of the inner wall into a plurality of condensing surfaces parallel to the axis of'the unit, a support for holding said unit in a vertical position and having a passage therethrough for placing the condensing surfaces in communication with vapors to be condensed, and a product line passing through a Wall of said support and having a condensate receiving opening arranged to receive the condensate from one of said surfaces.

3. In a joint for use between a vaporizing apparatus and a distilling head, a socket portion for receipt of the distilling head and a hollow apertured plug for 'establishing communication between the head and the vaporizing apparatus, a conduit arranged to capture part of the condensate from the head, a second conduit affording a passage into the joint available for introduction Baker June 13, 1899 Name Date Pattison Jan. 5, 1897 Hiller T- Feb. 5, 1901 Claude Mar. 10, 1908 Armstrong Feb. 28, 1922 Mort July 2, 1867 FOREIGN PATENTS Country Date Germany Feb. 4, 1930 Austria Aug. 15, 1905 Germany Sept. 16, 1930 

